The present invention relates to a surgical electrode for use in laparoscopic surgery and in particular to an instrument designed for deep surgical procedures involving tissue separation, dissection, and cauterization; as for example, deep thorax, intra-abdominal, deep rectum, and deep gynecological operations.
Laparoscopy has long been a standard form of treatment for gynecologic diseases and more recently has shown some promise in general surgical disorders, for example, certain abdominal disorders such as cholelithiasis, appendicitis, and intra-abdominal adhesions. The use of laparoscopy in general surgery has increased in recent years with the increased usage of laser energy for cutting and coagulation. Other modes of cutting energy include scissors, endothermic and electrical energy.
In general laparoscopy is performed by inserting a scope through one trocar or sheath and a surgical instrument through one or more other trocars or sheaths. The trocars are sleeves which are inserted through a body opening which may be a surgically made opening or portal through the skin, muscle and peritoneal membrane. The trocar typically has an inside diameter of 10 millimeters. The instrument for insertion through the trocar typically has an outside diameter of about 5 millimeters. Often the body cavity, such as the abdominal peritoneal area is inflated with low pressure carbon dioxide. An insufflation pressure of about 12 millimeters of HG or less is maintained during the operation by a sealing membrane located in the trocar opening comprising a thin rubber material having a small diameter hole of approximately 3 millimeters therein. The 5 millimeter diameter instrument is inserted through the membrane hole which stretches to accommodate the larger size thereby forming and effective seal.
Each of the forms of cutting energy used in laparoscopy have certain limitations and drawbacks. In particular, laser cutting and coagulation is a slow tedious, time consuming and costly procedure. The instrumentation required is highly sophisticated and expensive. Each pass of the laser beam at safe energy levels results in a shallow cut. Any smoke resulting from the cut and cauterization can interfere with subsequent laser beam passes. The smoke diffuses the energy from the cut area requiring additional time and/or procedures for clearing the body cavity of smoke.
Scissors, of course, are useful and can be manipulated within the body cavity, however, the dissection with the use of scissors does not simultaneously cauterize and requires additional steps to stop the bleeding and to keep the operating area clear of blood. Where electrical cauterizing energy is used at the scissor blades, tissue sticks to the blades and pulls loose causing bleeding and requiring a repeated removal of the scissors for cleaning.
Endothermic has limited applications and requires complex procedures for its proper usage.
The use of electrical energy with prior known blade configurations including hook electrodes and spade electrodes are subject to various common drawbacks as well as specific drawbacks with respect to each type of electrode. Both electrodes can accomplish cutting and cauterizing to a certain degree simultaneously. However, the electrode cutting results in substantial charring of the tissue cut. There is a significant amount of smoke generated within the body cavity, thereby obstructing the view of the surgeon through the laparoscope. Further, on prior known laparoscopic instruments the charred tissue sticks to either the hook or the spatula electrode surface which often causes tearing and pulling of the tissue, thereby re-opening the previous cauterized cut area to bleeding. The build up of tissue on the electrode surface interferes with transfer of electrical energy so that the electrode must be withdrawn periodically and repeatedly for cleaning before continuing the operation.
Specifically, hook electrodes, as the name implies, are used to go around a structure or tissue such as a duct or an artery, thereby pulling the structure away from surrounding tissue while the electrical energy is applied. This often results in cumbersome procedures for engaging and then disengaging the electrode to complete the surgical procedure. A Hook electrode may be used to pull tissue sideways to the right or to the left, but in changing from one to the other, the hook electrode must be turned 180.degree. along its long axis, making it inconvenient to use.
Spatula electrodes are pointed instruments having one concave surface and an opposed convex surface, and typically have a hole through the face of the spade-shaped tip to allow smoke to escape. Spatula electrodes are not well adapted for pushing or pulling tissues for the separation thereof because of the curved edges of the blade which terminates at a point and also because of the surface convexity and concavity, and they cannot pull tissue edgeways, or hold tissue with a edgeways pull.